Field of the Invention
The present invention relates to an imaging apparatus and an imaging method, and more particularly to an imaging apparatus having an automatic focusing function.
Description of the Related Art
General focusing methods for imaging apparatuses include a contrast autofocus (AF) method and a phase difference AF method. Both the contrast AF method and the phase difference AF method are AF methods that are widely used for video cameras and digital still cameras, in some of which an image sensor is used as a focus detection sensor.
In such focusing methods, the focus detection result may have an error due to various aberrations of an optical system. Therefore, various methods for reducing the error have been proposed.
For example, Japanese Patent No. 5087077 discusses a method for calculating a correction value used to correct a focus detection result based on an evaluation frequency (evaluation band) of a signal used for focus detection.
Such a focus detection error occurs depending on the evaluation band of a focusing signal used in the contrast AF method or the phase difference AF method regardless of the types of focusing methods.
However, the above-mentioned conventional proposals have such an issue that it is not possible to sufficiently correct a focus detection error. The method discussed in Japanese Patent No. 5087077 includes specifying, as a focus detection error, a frequency band (evaluation band) for evaluating a focusing signal, and correcting the focus detection result using a correction value adapted for the evaluation band.
On the other hand, the focus detection error is a difference between a focusing state that is sensed by the observer to be a best in-focus state as an original captured image and a focusing state that is indicated by the focus detection result. However, Japanese Patent No. 5087077 has no mention of the focusing state of a captured image.